Why Onions Make You Cry, and How to Stop the Tears for Good

Do You Dread Cutting Onions?

Onions are a kitchen staple that usually end up in my cart when buying weekly groceries. They’re as versatile as potatoes and can be used in recipes throughout the day. From omelets to salads, stir-fries, soups, stews, and even caramelized, onions can make a dish shine. Some may disagree, but whether you love or hate onions, there’s one thing we can also agree on disliking: the fact that onions make you cry. And in my case, my eyes run like a faucet the second a knife slices through the outer layer. I love the flavor, but I honestly dread having to cut them. But what causes the tears, and can you slice onions without torturing yourself?

Why do Onions Make You Cry?

The reason why onions make you cry is as cool as it is slightly terrifying. The tears are the byproduct of a defense mechanism onions have. As onions grow, the roots absorb sulfur and other enzymes in the soil. When an onion is cut or damaged, those enzymes and sulfur combine to create Propanethial S-oxide, which creates sulfuric acid when mixed with water. When onions make you cry, it’s from Propanethial S-oxide spraying into the air and mixing with the water on the surface of your eye. Your eyes then defend themselves by creating tears and possibly a runny nose to flush the acid away. While all onions cause the reaction, some varieties are worse than others.

Do All Varieties of Onions Make You Cry?

While all onion varieties contain Propanethial S-oxide, some contain more than others. The biggest factor to remember is that the roots of an onion are most vulnerable to predators and will have the highest concentration of sulfur. As onion stalks grow, the sulfur and enzyme contents decrease farther away from the root. Thats why the stalks of green onions, leeks, and chives cause fewer tears. You may still experience some eye irritation, but not as much as with pungent onions, including red, white, and yellow varieties. Shallots also make the list of tear-inducing onions. The bad news? The varieties of onions that make you cry are the most commonly used in recipes, especially yellow.

Does Soil Affect Whether Onions Make You Cry?

Absolutely! The soil that plants grow in can have a significant impact on the taste and color of fruits and vegetables. And in the case of onions, if a soil has lower amounts of sulfur, the onions will have less sulfur to absorb. If they can’t absorb as much sulfur as other growing regions, the onions will be sweeter. That’s why Georgia is known for having sweeter onions.

How to Reduce Tears Cutting Onions

Now that we’ve covered why onions make you cry let’s cover how to stop the tears for good. Unfortunately, there isn’t a way to grow onions without any tear-inducing compounds. While you can’t eliminate the sulfur and enzymes in an onion, you can reduce the sulfuric acid creation! The best hack to stop onion tears is to create a barrier between your eyes and the air.

Products to Reduce Onion Tears

Are safety glasses that give a throwback to high school science class chic? No. Do they seal your eyes and prevent tears? Yes. They also provide plenty of room to fit over prescription glasses. For a less scientific look, onion glasses offer a more flattering look in the kitchen but don’t fit over prescription glasses. Swimming goggles also work fine for cutting onions! All that matters is that the glasses create a seal around your eyes. If you need to cut onions but don’t have a form of eye protection, there are ways you can cut an onion to reduce tears.

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Onion Cutting Tips

Because the roots of an onion absorb the sulfur and enzymes in the soil, the highest concentration of compounds will release there. Cutting an inch above the root will release less absorbed oxides and cause fewer tears. Keeping the root intact will also make dicing easier!
Soaking onions in ice water or placing them in the fridge for thirty minutes before cutting can reduce tear production. Because gasses slow down when chilled, they won’t project into the air as far. There may still be tears, but not as much as if you cut into a room-temperature onion.
A sharp knife will also produce fewer onion tears than a dull knife. If a knife is dull, the edge tears through an onion rather than creating a clean cut. The cleaner the cut, the fewer onions cells will be broken, and less sulfur will be released.
Cutting onions in a well-ventilated area can help pull some gasses away from your face. Cut onions near an open window or exhaust fan to reduce tears. The added airflow will help circulate the air around an onion away from your face.

Do Onions Make You Cry Because of an Allergy?

Some people seem lucky and don’t tear up as much when cutting onions. That can lead to confusion about whether or not you may be allergic to onions, just like some people aren’t allergic to poison ivy. While it’s possible to be allergic to onions, the tears caused by cutting an onion aren’t necessarily the symptom of an allergic reaction. It’s a defense your eye uses against sulfuric acid. Symptoms of a food allergy to keep an eye out for include, but are not limited to:

Itching
Body rashes or hives
Vomiting
Nausea
Diarrhea
Swelling of the face, eyes, and tongue
Difficulty breathing
Wheezing

If you suspect that you or someone else is having an allergic reaction, call 911 right away. If you suspect you may have a food allergy, you can also contact your doctor or other licensed medical professionals to conduct a food sensitivity test to confirm or rule out any potential allergens. Information at Flavors of Paradis LLC is not intended to replace professional medical advice and should be used at your own risk.

You Don't Have to Suffer Cutting Onions

The next time a recipe calls for onions, you don’t have to dread cutting them! Keep a pair of swimming goggles nearby and avoid the root when cutting if onions make you cry. Don’t forget to open a window or use an overhead fan if you don’t have goggles and chill them in the fridge a half hour before cutting. If you have any tricks you use at home to stop onion tears not listed here, I’d love to hear them in the comments!